Churg-Strauss syndrome

Churg-Strauss syndrome is a rare condition characterised by asthma and blood eosinophilia together with an eosinophilic vasculitis

Also known as Eosinophilic granulomatosis with polyangiitis (EGPA)

The estimated prevalence of the disease is approximately 1 to 3 per million adults worldwide. The mean age of onset ranges between 38 and 54, with a median of 40. (1) Gender prevalence is similar between males and females. (2)

Regardless of age, both adult and childhood EGPA present with highly elevated IgE and eosinophil levels. About 40% of adults with EGPA have a positive ANCA, whereas 25% of children are seropositive for this. (3)

The initial phase of the disorder is one of asthma and allergic rhinitis, often followed by peripheral blood eosinophilia with eosinophilic tissue disease. The vasculitic phase that follows is life-threatening but can often be treated effectively with immunosuppression.

• eosinophil-rich and necrotising granulomatous inflammation often involving the respiratory tract, and necrotising vasculitis predominantly affecting small to medium vessels, and associated with asthma and eosinophilia. ANCA is more frequent when glomerulonephritis is present
• characteristic features of EGPA are asthma (typically late-onset), peripheral blood and tissue eosinophilia, fever, and systemic vasculitis
• asthma especially distinguishes EGPA from granulomatosis with polyangiitis (GPA, previously known as Wegener’s granulomatosis) and microscopic polyangiitis (MPA)
• renal involvement is relatively uncommon.
• asthma is the cardinal feature and precedes systemic features in virtually all cases; onset is late in life and becomes more severe until the onset of vasculitis
  • chest x-ray shows infiltrates in <=77%
• cardiac disease is common (<=47%) and is an important cause of mortality, due to congestive heart failure, pericardial effusion and restrictive cardiomyopathy
• mononeuritis multiplex is a common (70%) feature of EGPA, where it is much more frequent than in GPA and MPA

Management (4)

• induction treatment for most patients with ANCA associated vasculitis (AAV) should be with cyclophosphamide or rituximab and glucocorticoids
• AAV should be considered to be a chronic disease needing long term immunosuppressive therapy
• rituximab should be considered as an alternative induction agent for those at high risk of infertility and infection
• although earlier evidence suggested that induction with rituximab may be especially useful in ANCA-positive EGPA, the REOVAS trial found no significant differences between cyclophosphamide and rituximab (5)
• mortality remains high, and late death is due to cardiovascular disease, infection (secondary to treatment) and malignancy

References:

1. Walulik A ET AL. The Role of Neutrophils in ANCA-Associated Vasculitis: The Pathogenic Role and Diagnostic Utility of Autoantibodies. Int J Mol Sci. 2023 Dec 07;24(24)
2. Harrold LR et al. Incidence of Churg-Strauss syndrome: a population-based perspective. J Rheumatol. 2005 Jun;32(6):1076-80.
3. Fijolek J, Radzikowska E. Eosinophilic granulomatosis with polyangiitis - Advances in pathogenesis, diagnosis, and treatment. Front Med (Lausanne). 2023;10:1145257.
4. Hellmich B et al. EULAR recommendations for the management of ANCA-associated vasculitis: 2022 update. Ann Rheum Dis. 2024 Jan 02;83(1):30-47
5. Terrier B et al. French recommendations for the management of systemic necrotizing vasculitides (polyarteritis nodosa and ANCA-associated vasculitides). Orphanet J Rare Dis. 2020 Dec 29;15(Suppl 2):351